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-   -   Checksum question (https://www.evolutionm.net/forums/ecu-flash/734383-checksum-question.html)

rumpig Oct 29, 2016 03:18 AM

Checksum question
 
Hi,


Does anyone know how Mitsubishi calculate the checksum for SH7052 once it goes above FFFF . The only info i can find suggests you drop the hi byte and use the 4 low bytes but it must keep track of the rollover to remain accurate. I know ecuflash does the checksum but i'm working on my bike and am having to do it manually.


Alternatively could someone stick my bin file in idapro and switch off the checksum for me.

tephra Oct 29, 2016 09:54 PM

its a rolling additive...

ie 0xffff + 0x0002 = 0x0001...

overflow is lost/not kept...

rumpig Oct 31, 2016 02:31 AM

That's what I have been trying, i'll keep at it and see how I go.
Thanks


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